Page layout template association cannot be changed if the current template is missing

• Type: Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: 6.1.2 CE GA3, 6.1.30 EE GA3, 6.2.0 CE GA1, 6.2.10 EE GA1
• Fix Version/s: 6.1.X EE, 6.2.2 CE GA3 , 6.2.X EE, 7.0.0 M1
• Component/s: Pages > Page Administration, Site Templates, Sites Administration > Sites
• Labels:
  • ee-ts
  • liferay-fixpack-platform-23-6130
  • liferay-fixpack-platform-7-6210
• Branch Version/s:
  6.2.x, 6.1.x
• Backported to Branch:
  Committed
• Story Points: 5
• Fix Priority: 4
• Git Pull Request: https://github.com/brianchandotcom/liferay-portal/pull/16601

The issue is about a very rare, however, possible scenario, when the referenced LayoutTemplate (Page Layout) (for example: 2 Columns (70/30)) is missing. Now, a user is unable to change the template for a page (Layout) that uses a missing template.

For example, after an upgrade, it can take more time for users to upgrade their custom themes & templates, thus, to overcome this, it can happen they want to change the template associations to an available one temporarily.

Here are the steps to reproduce the annoying problem:
1- Start portal
2- Edit "Welcome" page through the side bar
3- Change template to 2 Columns (50/50)
4- Save
5- Stop portal

6- Navigate to $TOMCAT_HOME/webapps/ROOT/WEB-INF
7- Edit liferay-layout-templates.xml: comment-out the "layout-template" element for 2 Columns (50/50). Save.

8- Start portal
9- Edit "Welcome" page through the side bar

10- You can see that there is no "Template" selected as current one.
11- Select another template
12- Save

Expected result
New template should be saved.

Actual result
Page gets reloaded, but the layout is still the default one, defined in portal.props

layout.default.template.id=2_columns_ii

and the new template association has not been saved.